Transformer



E. N. A. RAULAND TRANSFORMER Filed July 1922 1A VENTOR f. /i/. Ha/@7745ATTORNEY Patented Dec. 30, 1924.

UNITED STATES EINAR N. A. RA'ULAND, 0F CHICAGO, ILLINOIS.

TRANSFORMER.

Application led July 1,

T o all whom z't may concern:

Be it known that EINAR N. A. RAULAND, a citizen of the United States,and residing at 1516 North Lorel Avenue, Chicago, Illinois, has inventedcertain new and useful Improvements in Transformers, of which thefollowing is a specification.

This invention relates to transformers and more particularly totransformers adapted for use in radio telegraphy and. telephony. It isthe object of the present invention to provide a transformer of simple,sturdy and compact design and one which may be readily associated withand disassociated from a circuit in which it is to be used. y

`With this object in View the transformer constructed in accordance withthe present invention is so arranged that its association with thecircuit may be effected either by connecting the circuit conductors withthe terminals of the transformer coils in the usual manner through theagency of binding posts or through a socket such as a lamp socket, andmore particularly a type of socket adapted to receivelan audion or othervacuum 'tube device. YIn accordance with the present embodiment of theinvention, the contacts of the socket are engaged by said terminalsacting as wipers or contact makers. Due to such arrangement, thetransformer forming the subject of the present invention may be eithermounted on a panel in the usual manner or inserted in a socket like alam or tube.

It should be noted also that the foregoing eneral description of theinvention and the etailed description to follow are in no way intendedto limit the scope of the present invention for which reference shouldbe had to the appended claims.

In the drawings Fig. 1 is a side view and Fig. 2 a top view of a radiofrequency transformer constructed in accordance with the presentinvention; Fig. 3 is a sectional View along lines 3-3 of Fig. 2; Fig. 4shows the transformer core in perspective; Fig. 5 the mounting for thetransformer core and Fig. 6 shows the socket arrangement to receive thetransformer.

1 is a cylindrically shaped case of suitable material such as brass,having a closed top 2 in which four holes are provided for permittingthe vpassage of lugs 3, 4, 5 and 6. The lower end of the case bulges outat 7 and an insulated bottom late is set in the groove formed by bulge7. he overhanging edge 9 1922. Serial No. 572,317.

of case 1 is then turned down on the bottom plate 8. The bottom plate 8is rovided with two ears 10 and 11 respective y, perforated at 12 and 13respectively, the bottom plate being set in lace with the ears 10 and 11engaging note es 14 and 15, respectively, cut out of the lower edge ofcase 1.

The primary and secondary windings of the transformer are provided on acylindrical wooden core 16 and are wound within grooves 17 and 18provided on the core. The core is perforated at 19 to facilitate thewinding operation. The core 16 is held against a disc 2() of insulatingmaterial by means of two screws 21, the distance between the core andthe disc being determined by bushings 22. The screws 21 engage the core16 at right angles to its axis and the grain of the wood, and to the riht and left, respectively, of the grooves 1 and 18. Four holes 23 areprovided in the disc for permitting passage of the lugs 3, 4, 5 and 6.

In assembling the transformer, after the core 16 is wound, it is securedto the disc 20 by means of the screws 21. The ends 24 and 25 of theprimary and secondary windings are then secured to the lower ends of thelugs 3, 4, 5 and 6 and these lugs are pushed through the holes 23. Thedisc is then set as shown in Fig. 3 against the top 2 of the case withthe lugs 3 6 projecting through the holes provlded therein. The axis ofthe core 16 is at right angles to the axis of the case 1. The clearancebetween the holes provided in the top 2 and the lugs is filled in withwashers 26 of insulating material. The protruding ends of the lugs arescrew-threaded. By means of nuts 27 engaging the screw-threaded portionsof the lugs, the disc 20 is held securely against the top 2, washers 28of insulating material separating the nuts 27 from the top 2. By meansof thumb screws 29 and 30 engaging the screw-threaded ends of the lugs,these lugs may be em loyed in the usual manner to act as bin ing postsfor the conductors of a circuit with which the transformer is to beconnected. In this case the transformer is fastened to a panel by meansof screws engaging the ears 10 and l1.

For the purpose of permitting the use of the transformer in combinationwith an audion tube socket 40, a lug 41 projecting from the case l is solocated that when the transformer is inserted within the socket- 40 withthe lugs 3 6 pointing down# ward and the lug' 40 engaging an L shapednotch 42 in the socket, the desired connection will be had between lugs3, 4, 5 and 6 and the contacts of the socket 40 which are', of course,suitably wired to the circuit.

The advantages of arranging the transformer to cooperate. with a socketare manifold. First, the leads between the coils and the circuit withwhich it is to be connected are shortened as compared with the leadsnecessary in connecting a transformer mounted in the usual manner,whereby inductance and capacity losses that are caused by long leads arematerially reduced; second, the transformer may be readily associatedwith the circuit; and third, the proper connection with the variousparts of the circuit is insured by the.; relative location of the coilterminals andthe contacts of the socket. This rapid and accuratereplacement of one transformer by another in a circuit is of particularimportance in radio receiving stations in which it is preferable tdemploy differently wound transformers (particularly radio frequencyamplifying transformers) for different ranges of wave lengths.

For the purpose of further reducing inductance and capacity losses, theleads between the transformer coils and said terminals are also made asshort as possible. In the present instance, this is accomplished by therelative positioning of the transformer coils and the surrounding case.The case is of substantially cylindrical shape to Iit within sockets ofcommercial type, and the transformer windings are provided on asubstantially cylindrical wooden or insulating core the axis of which isat right angles to the axis of the case. Due to this arrangement thetransformer coil terminals or leading' out wires are brought relatively'near the end of the case through which the terminal posts project, Thecase is preferably of metal such as brass and acts as a shield for thetransformer.

The mentioned relative positioning of the case and core has also furtheradvantages. The turns of the coils mounted on the core are on theaverage at a relatively great distance from the side walls of the casewhereby eddy and other losses caused by induction, etc., are. less thanif said turns were nearer the case by mounting the core in the casecoa-xially.

Still a further advantagexconsists in making possible a simple mountingof the core without interfering with the efficiency thereof. Inaccordance with the present embodiment of the invention, this isaccomplished by fastening the coil to the case, preferably through theagency of a disc of insulating material, by suitable means such asscrews which engage the core at right angles to its axis, the disc beingheld against the top of the case through the agency of the terminalposts. As above stated, the core is preferably of wood (maple) and itsengagement by said screws at right angles to the grain of the wood willbe less likely to cause splitting than if the screws were forced in thewood in the direction of the grain, and the screws will, of course, holdbetter. Furthermore, if the core were coaxial with the case, it would benecessary to mount it by passing a screw, bolt or the like through thecenter thereof and therefore through the centre of the coils. As is wellknown, this would cause eddy and other electrical losses. In the presentcase no metal need pass through the centre of the coils, the mentionedmounting screws projecting only to a slight distance within the core andbeing located on the two sides of the coils. The metallic case withinwhich the core is mounted has a closed top provided with four holesthrough which the terminal posts project. The core mounted on thementioned dise of insulating' material is inserted through the openbottom ot' the case and then the case is poured full of some suitablesealing compound which will protect the transformer coils againsthumidity, etc. The mentioned grooves in the core are not entirely filledwith the transformer coils, and the sealing compound will be depositedin these grooves to seal in the coils.

Two notches are provided at the open end of the case and are so locatedas to receive two ears provided on a disc which serves as the bottomplate of the case. -ifter the bottom plate is set in place theoverhanging edge of the case is turned down so as firmly to hold thebottom plate and to insure a proper clamping. This bottom plate ispreferably of insulating material or is coated with some insulatingcompound whereby eddy currents in the case will not find a completecircuit through which they may pass. In this connection it should benoted that the transverse mounting of the -coils in the case causes themain induced currents in the case to flow in the direction of the turnsof the coil mainly through the longest possible path which is madelonger by the insulation of the bottom plate.

In accordance with the present disclosure. the transformer is locked ina suitable socket by means of a bayonet joint connection. For thispurpose a lug projects from the case and cooperates with an L shapedslot in the socket. The said two ears in the bottom plate are providedto serve as abntments for the thumb and index nger of the user wheninserting the transformer in the socket. The ears are also perforatedfor facilitating the mounting of the transformer on a panel.

lOO

It will be obvious to those skilled in the art that variousmodifications are practicable in the transformer structure forming thesubject matter of the present invention without departing from thespirit thereof. The bayonet joint connection between the transformercase and the socket may be replaced by any other suitable connection.The terminal posts need not necessarily be provided in a manner toenable the use of this transformer in the conventional manner, andbinding posts or contacts of any well known shape and arrangement may beused. While I found a substantially cylindrical wooden core satisfactoryand most economical for the present purpose, cores of other materialsand shapes may be used and still obtain some of the important advantagesof the present invention.

vWhat I claim is: 1. In a transformer adapted to be inserted in and tocooperate with a vacuum tube socket having four contacts, asubstantially cylindrical case, a substantially cylindrical core withinsaid case, the axes of said core and case being at an angle to eachother, two transformer coils provided on said core adjacent to eachother, and terminals for the transformer coils projecting insubstantially the same direction through said case.

2. In a transformer adapted to be inserted in and lto cooperate with avacuum tube socket having four contacts, a substantially cylindricalcase, a substantially cylindrical core within said case, the axes ofsaid core and case being at right angles to each other, two transformercoil windings provided on said core substantially parallel to each otherand at right angles to the axis of said core, and terminals for the coilwindings projecting through one end of said case.

3. In a transformer adapted to be inserted in and to cooperate with avacuum tube `socket having four contacts, a, cylindrical case, acylindrical core within said case, the axes of said core and case beingat right angles to each other, two transformer coil `windings providedon said core substantially parallel to each other and at right angles otlie axis of said corea and terminals Vfor the coil windings projectingthrough one end of said case.

4. In a transformer, a cylindrical metal case, a cylindrical wooden corewithin said case, the axes of said core and case 'being at right anglesto each other, and lugs projecting through one end of said case servingas a means for holding said core and as terminals for the'coil windings.

,5. In a transformer adapted to be inserted in'and to cooperate with avacuum tube socket having four contacts, transformer windings, a caseenclosing said windings, contact points projecting from said casewindings, Contact points projectin and serving as terminals for saidwindings, all of said termina-ls arranged to engage the contacts of thesocket.

6. In a transformer adapted to be inserted in and to cooperate with avacuum tube socket `having four contacts, transformer windings, a caseenclosing said windings, contact points projecting from said case andserving as terminals for said windings, all of said terminals arrangedto engage the contacts of the socket.

7. In a transformer adapted to be inserted in and to cooperate with avacuum tube socket having four contacts, transformer windings, a caseenclosing said from said case and serving as terminals or said windings,a notch in said socket, a lug projecting from said casing and arrangedto engage said notch-to cause the cooperation of all of said contactpoints with the contacts of said socket in a predetermined manner.

8. In a. transformer adapted to be inserted in and to cooperate with avacuum tube socket' having four contacts, a substantially cylindricalcore carrying the transformer windings, a cylindrical case enclosingsaid core, the axis of the latter being at right angles to the axis ofthe case, contact points projecting through said case and serving asterminals for the transformer windings, all of said terminals arrangedto engage the contacts of the socket.

' 9. In a transformer adapted to be inserted in and to cooperate with avacuum tube socket having four contacts, a substantially cylindricalcore, transformer windings mounted thereon, a cylindrical case enclosingsaid core, the axis of the latter being at right angles to the axis ofthe case, means for holding. said core at a certain distance lfrom oneend `of said case, four lugs projecting through said end of the case,the lower ends of said lugs serving as terminals for the transformercoils and the projecting ends as contact points or binding posts, abottom plate for said case having two perforated ears, a notch in saidsocket, a lug projecting from said case and cooperating with said notchin such a manner that when said case is locked in place 'the fourprojecting lugs engage the conmaterial within Asaid case and betweensaidcore and the top, two screws for holding said core -at a certaindistance from said disc, four lugs 'projecting from the disc'throughsaid top, the lower ends of said lugs serving as terminals forthetransformer coils and the projecting ends as contact points and bindingposts, an insulated plate for closing 'the bottom of said case, a notchin said socket, a lug projecting from said case 'and coopera-ting withsaid notch in such a manner that when said case is locked in place thefour projecting lugs engage the contacts of said socket in apredetermined manner.

ll. In a transformer adapted to be inserted in and to cooperate with avacuum tube socket having four contacts, an impregnated wooden corehaving a cylindrical shape and being perforated through its centre,parallel grooves near the centre of said core at right angles to theaxis thereof, transformer windings partly iilling said grooves, acylindrical metal case enclosing said oore, the axis of the latter beingat right angles to the axis of the case, a top for said case, a circulardisc of insulating material within. said case and between said core andtop, a sealing compound filling said' grooves and the open spacesbetween said core and case,.two screws forholding said core-at a certaindistance from said disc projecting through said disc and into said coreat right angles to the grain of the wood and near the ends of the core,four lugs projecting `from the disc through said top, 'the lower ends ofsaid lugs serving as terminals for the transformer coils and theprojecting ends of said lugs being screwthreaded to receive binding postnuts, washers of insulating material between said nuts and the top,notches in the open end of said case, an insulated bottom plate for saidcase having two ears engaging said notches, a substantially L shapednotch in said socket, a lug projecting from said case and cooperatingwith said notch in such a manner than when said case is locked in placevthe four lugs engage thecontacts of said socket in a predeterminedmanner.

In testimony whereof, I have signed my name to this specification thistwenty-sixth day of June 1922.

EINAR N. A. RAULAND

